Aristippus, fragment 208 Mannebach = Aelian, Historical Miscellany
14.6 (tr. Robin Hard):
Aristippos was thought to have made a very sound point when he urged
people not to worry afterwards about things that have gone by, or worry in
advance about those that are yet to come. For such an attitude is a sign of
confidence and gives proof of a cheerful frame of mind. He recommended that
one should concentrate on the present day, and indeed on the very part of it in
which one is acting and thinking. For only the present, he said, truly belongs to
us, and not what has passed by or what we are anticipating: for the one is gone
and done with, and it is uncertain whether the other will come to be.
πάνυ σφόδρα ἐρρωμένως ἐῴκει λέγειν ὁ Ἀρίστιππος παρεγγυῶν τοῖς ἀνθρώποις μήτε τοῖς παρελθοῦσιν ἐπικάμνειν μήτε τῶν ἐπιόντων προκάμνειν· εὐθυμίας γὰρ δεῖγμα τὸ τοιοῦτο καὶ ἵλεω διανοίας ἀπόδειξις. προσέταττε δὲ ἐφ᾿ ἡμέρᾳ τὴν γνώμην ἔχειν καὶ αὖ πάλιν τῆς ἡμέρας ἐπ᾿ ἐκείνῳ τῷ μέρει, καθ᾿ ὃ ἕκαστος ἢ πράττει τι ἢ ἐννοεῖ. μόνον γὰρ ἔφασκεν ἡμέτερον εἶναι τὸ παρόν, μήτε δὲ τὸ φθάνον μήτε τὸ προσδοκώμενον· τὸ μὲν γὰρ ἀπολωλέναι, τὸ δὲ ἄδηλον εἶναι εἴπερ ἔσται.